pika strings -- back to hacking

hi,

well, i have had a couple of unexpectedly busy months that had
prevented my hacking pika. fortunately, i've recovered my free time,
and have begun implementing the pika/hackerlab unicode string stuff
(remember? ;)).

following tom's guidelines, the first thing to do was converting
uni_string to a union type, and update its usage accordingly. i have
just implemented it, and it's available at my usual mirror for
merging ([email protected]/hackerlab--devo--1.0). comments:

- i've typedef'ed the uni_string union, partly to save me the work of
  changing the numerous uni_string declarations to 'union uni_string'
  and partly because i like it better: is this ok?

- i've put some inline uni_string functions
  unicode/uni-string-inlines.[hc], but i'm really sure if this is the
  proper place. as a matter of fact, i don't yet understand the roles
  of uni, unidata, unicode libs (in the sense of where a given
  functionality belongs). but this should be fixed with a little more
  code reading, i guess.

- the 'hairy macros' in coding.h and str.c have been a little bit
  simplified due to the uni_string type change. they don't handle
  utf32 yet, though.

- i've made small, blind modifications to re-xml, just to make it
  compile and pass the tests: it'd be great if someone knowledgeable
  reviewed them (tom? :)

i think that's all by now. if you don't see anything fatally wrong in
the above, i'll go on to the next step (utf32 support in hackerlab)
based on it.

jao
-- 
Yet it is in our idleness, in our dreams, that the submerged truth
sometimes comes to the top.
   - Virginia Woolf (1882-1941), A Room of One's Own, (1929).